BASEMENT FLOODING MITIGATION
Understanding Chicago's Combined Sewer System​
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In the past, water was able to gradually soak into the ground in open areas that are now covered with driveways, streets, parking lots, etc. Today, an estimated 42% of Cook County is impervious surface, meaning water from Chicago's recent record-breaking storms cannot be absorbed. We have removed the natural absorptive capacity of our landscape giving the rainwater nowhere to go. As a result, basement flooding and stormwater management has become a huge issue in Chicago, and for our Chicago bungalows.
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During heavy rains, Chicago's 100 year old combined sewer system may reach capacity resulting in backup. In a combined sewer system, sanitary sewage and stormwater drain into the same pipes. Homes, businesses and street drains are connected to the local sewers, which are owned and maintained by municipalities. Local sewers flow by gravity into the Metropolitan Reclamation District of Greater Chicago (MWRD) intercepting sewers, which then convey the flow to MWRD water reclamation plants for treatment.
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The City of Chicago certainly has a responsibility to help mitigate the impact of storm water, but as homeowners, we play a large role in managing the stormwater that falls onto our property. We are all responsible for water management in Chicago, and collectively we can make a difference.
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The information below was provided by Ryan Wilson of Elevate Energy in partnership with CBA's Basement Flooding seminars, thanks to a grant from the Illinois Department of Natural Resources (IDNR). Use this as a guide to learn what problems to look for, where and when to look for them, low cost improvements, plus helpful hints and next steps.
Identifying Flood Risks at Your Property
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Before you can manage water on your property, it's important to identify which type of flooding you are dealing with.
There are 3 types of flooding
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Water & Sewer Backup
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Foundation Seepage
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Yard Flooding
Image Courtesy of: Institute for Catastrophic Loss Reduction
Backup through Drains, Sump Pumps, Sinks, Tubs & Toilets
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What to look for
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Standing water (clear, dirty, sewage)
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Stains on walls & floors
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Sediment near drains, open sump pumps
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Where
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Near floor drains, open sump pumps
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Basement sinks, tubs , toilets
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When
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During rain
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After rain
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Hint: Check your basement during and after rains. Standing water after rain stops
could mean blocked pipes.
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Next Step: Hire a licensed plumber to televise building sewer
Seepage at Cracked or Porous Foundation​
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What to look for
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Water coming from walls
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Cracks in exterior walls
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Where
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Foundation walls in basement
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Seam of wall and floor (cove joint)
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Pipe penetrations at foundations
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When
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During rain
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After rain
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Dry weather
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Hint: Look for water stains on the floor, peeling paint, or powder-covered brick.
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Next Step: Run a garden hose for 30 min to an hour to test cracks;
consult foundation repair contractor
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Leaking Window Wells or Doors​
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What to look for
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Gaps near basement windows & doors
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Damage to door seals & window weather stripping
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Water or water damage at window sills
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Where
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Basement windows or doors
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When
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During rain
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After rain
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Hint: Window or stairwells without drains are common sources
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Next Step: Inspect condition of doors and windows
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Downspout Discharge Near Foundation​
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What to look for
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Broken or obstructed downspouts
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Disconnected or missing downspouts
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Where
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Exterior perimeter of home
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When
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During rain
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Hint: Bungalows often have 2 or more downspouts to drain the many roof areas.
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Next Step: Inspect downspouts in dry weather, and again during rain.
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Low Points near Foundation​
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What to look for
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Standing water during and after rain
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Perennially wet soils
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Where
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Near foundation
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When
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During rain
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After rain
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Dry weather
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Hint: Soils around buildings settle over time; downspout discharge can scour
soil and create low points
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Next Step: Inspect foundation in dry weather, and again during rain.
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Low Points in Yard
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What to look for
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Standing water during and after rain
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Perennially wet soils
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Where
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Yard
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When
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During rain
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After rain
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Dry weather
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Hint: Look for places that are often wet or where grass doesn't grow.
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Next Step: Inspect yard in dry weather, and again during rain.
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Low or No-Cost Improvements
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Clean Gutters
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Why
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Water overflowing gutters
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Clogged or obstructed building sewers
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What to do
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Clear gutters
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Install gutter guards
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Considerations
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Take necessary safety precautions
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Disconnect Downspout from Building Sewer
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Why
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Water backup
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Downspouts are connected to building sewer
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What to do
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Cut downspout; remove connection from sewer
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Extend >10' from foundation
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Considerations
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Capture water on-site
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Don't send water to neighbors
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Extend Downspout to Yard
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Why
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Downspout discharges near foundation
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What to do
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Extend discharge 10' from foundation
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Considerations
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Capture water on-site
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Overflow route to right-of-way
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Don't send water to neighbors
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Caulk Joints & Cracks near Foundation
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Why
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Block point of entry for water​
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What to do
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Clean existing joints or cracks
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Caulk cracks; use foam backing
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Considerations
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Weather-resistant materials
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Other points of entry
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Foundation cracks may require contractor
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Don't send water to neighbors
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Slope Yard away from Foundation​
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Why
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Direct water away from foundation
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What to do
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Grade yard to drain away from foundation
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Considerations
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Add or remove soil
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Soil with high clay content
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Perennial plants
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Don't send water to neighbors
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Install a Rain Garden​
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Why
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Capture water from downspout or paved surfaces
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Improve drainage in yard
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What to do
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Size garden appropriately
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Plant perennials
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Considerations
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Storage volume
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Proximity to foundation
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Infiltration capacity of soils
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Don't send water to neighbors
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Install Rain Barrel(s) or Cistern
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Why
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Reuse water for irrigation
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What to do
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Disconnect downspout
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Attach a rain barrel
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Ensure necessary overflow route
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Considerations
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Size to serve source area(s)
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Discharge >10' from foundation
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Don't send water to neighbors​
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Install a Standpipe
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Why
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Stop water from entering basement
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What to do
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Install secure pipe connection to all floor drains
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Considerations
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Multiple drain locations
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Obstruction of walkways
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Height of pipe
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Condition of seal
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Hire Trusted Contractors​
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Foundation crack repair
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Sewer rodding & televising
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Backwater valve
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Interior drain tile
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Sump pump or ejector pumps
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Overhead sewer
Flooding Resources
Disconnected downspout near foundation
Low point near foundation
Low point near foundation
Low point in yard
Clean gutters
Image Source: mishaandmia.blogspot.com
Extend downspout to yard
Backer rod
Plant perennials
Install rain garden
Install rain barrel(s)
Install a standpipe
Watch "Basement Flooding: Reducing the Risk on Your Property"
Watch the recording of our August 2020 webinar presented by Ryan Wilson of Ryan Wilson Landscape Architecture. Ryan gives an in-depth exploration of the causes of flooding on your property, and identifies things you can do on the inside and outside of your bungalow or vintage home to help reduce flooding and sewer backups.
Private Drain Repair Program
Private Drain Repair is a program offered by the City of Chicago's Department of Water Management (DWM) offering repair of sewer drain tiles coming from private residences, of up to four units, that are broken under the public way. This is the area from the city sidewalk to the center of the street.
MeterSave
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MeterSave is a program offered by the City of Chicago's Department of Water Management (DWM) to non-metered Chicago homeowners to voluntarily install free meters to help them save water and save money.
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Customers with metered homes pay only for the water they use, they can save money while at the same time helping to protect Lake Michigan and save water.
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7 year guarantee that your home water bill will be no higher than it would have if the meter had not been installed
Green Neighbor Guide
In the Metropolitan Water Reclamation District of Greater Chicago (MWRD)'s Green Neighbor Guide, you will learn how to stop sending stormwater directly into the sewer by disconnecting the downspouts; how to install rain barrels or cisterns to capture stormwater for reuse; how to install dry wells and rain gardens to allow stormwater to filter into the ground; and how to replace asphalt and concrete surfaces with permeable paving to reduce stormwater runoff.
Use the symbols below to guide you on identifying and improving flood risks at your property:
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